Display device and method of inspecting the same

ABSTRACT

A display device includes a sensing line and a data driver. The sensing line is in a display panel. The data driver includes a plurality of integrated circuits. Each of the integrated circuits includes an interface, which includes a mobile industry processor interface (MIPI) and a crack detector. The crack detector detects cracks of the panel based on the sensing line and transmits and receives information corresponding to the crack to and from adjacent ones of the integrated circuits using a transmission terminal and a reception terminal in the MIPI.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2016-0150206, filed on Nov. 11, 2016,and entitled: “Display Device and Method of Inspecting the Same,” isincorporated by reference herein in its entirety.

BACKGROUND 1. Field

One or more embodiments described herein relate to a display device anda method for inspecting a display device.

2. Description of the Related Art

A variety of displays have been developed. Examples include liquidcrystal displays and organic light emitting displays. In manufacturingthese and other displays, multiple panels are formed on one mothersubstrate. The substrate is then scribed and divided into separatepanels. When the substrate is divided (e.g., cut), cracks may form inthe panels. Cracks may also occur as the result of various environmentalinfluences. When an overcurrent is supplied to a panel having a crack, afire may occur.

During manufacturing, an inspection may be performed to locate cracks ina panel. Also, when the panel uses multiple integrated circuits, amethod for resetting the integrated circuits in accordance with adetected crack may be performed.

SUMMARY

In accordance with one or more embodiments, a display device includes asensing line in a panel; and a data driver including a plurality ofintegrated circuits, each of the integrated circuits including aninterface which includes: a mobile industry processor interface (MIPI)connected to an external system; and a crack detector to detect a crackof the panel based on the sensing line and to transmit and receiveinformation corresponding to the crack to and from adjacent ones of theintegrated circuits using a transmission terminal and a receptionterminal in the MIPI.

The sensing line may include a first side connected to a firstintegrated circuit among the integrated circuits and a second sideconnected to a second integrated circuit among the integrated circuits.

The crack detector may include a voltage supplier/receiver to supply orreceive a voltage to or from the sensing line; a voltage detector todetermine whether the voltage from the voltage supplier/receiver is anormal voltage; and reset logic connected to the voltage detector totransmit and receive at least one of an error signal or a reset signalusing the transmission terminal and the reception terminal. The errorsignal may be indicative of the crack of the panel. The reset signal maycorrespond to an off state of the first and second integrated circuits.

The error signal may be sequentially supplied to the second integratedcircuit through the first integrated circuit. The reset signal may besequentially supplied to the first integrated circuit through the secondintegrated circuit. The reset signal may set the first and secondintegrated circuits in off states. When a level of the voltage is lowerthan a predetermined level, the voltage detector may determine that thevoltage is an abnormal voltage and is to supply a detection signal tothe reset logic. The reset logic may supply the error signal to anadjacent one of the integrated circuits.

Each of the integrated circuits may include a voltage source to output adriving power source; a data processor to rearrange data items suppliedvia the interface and to store the rearranged data items in a memory;and a channel area to generate data signals based on the data itemsstored in the memory. When the crack occurs in the panel, the crackdetector may set the source, the data processor, the memory, and thechannel are to be in off states. The sensing line may be at an edge ofthe panel.

In accordance with one or more other embodiments, a method forinspecting a display device including a mobile industry processorinterface (MIPI), the method comprising: supplying a predeterminedvoltage from a first integrated circuit in a data driver to a secondintegrated circuit in the data driver via a sensing line in a panel;determining, by the second integrated circuit, a level of thepredetermined voltage; and turning off integrated circuits in the datadriver when the voltage level is lower than a predetermined voltagelevel, wherein the first and second integrated circuits transmit andreceive information corresponding to crack of the panel using atransmission terminal and a reception terminal in the MIPI.

When the voltage level is lower than the predetermined voltage level,the method may include generating, by the second integrated circuit, anerror signal. The error signal may be sequentially supplied to thesecond integrated circuit through the first integrated circuit.

The method may include generating a reset signal, by the firstintegrated circuit, corresponding to the error signal. The method mayinclude sequentially supplying the reset signal to the first and secondintegrated circuits. The reset signal may turn off the first and secondintegrated circuits.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail exemplary embodiments with reference to the attached drawingsin which:

FIG. 1 illustrates an embodiment of a display device;

FIG. 2 illustrates an embodiment of a data driver;

FIG. 3 illustrates an embodiment of an integrated circuit;

FIG. 4 illustrates an embodiment of an interface unit;

FIG. 5 illustrates an embodiment of a panel crack detecting process andan integrated circuit resetting process; and

FIG. 6 illustrates an embodiment of a method for inspecting a displaypanel.

DETAILED DESCRIPTION

Example embodiments are described with reference to the drawings;however, they may be embodied in different forms and should not beconstrued as limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will convey exemplary implementations to those skilled inthe art. The embodiments (or portions thereof) may be combined to formadditional embodiments.

In the drawings, the dimensions of layers and regions may be exaggeratedfor clarity of illustration. It will also be understood that when alayer or element is referred to as being “on” another layer orsubstrate, it can be directly on the other layer or substrate, orintervening layers may also be present. Further, it will be understoodthat when a layer is referred to as being “under” another layer, it canbe directly under, and one or more intervening layers may also bepresent. In addition, it will also be understood that when a layer isreferred to as being “between” two layers, it can be the only layerbetween the two layers, or one or more intervening layers may also bepresent. Like reference numerals refer to like elements throughout.

When an element is referred to as being “connected” or “coupled” toanother element, it can be directly connected or coupled to the anotherelement or be indirectly connected or coupled to the another elementwith one or more intervening elements interposed therebetween. Inaddition, when an element is referred to as “including” a component,this indicates that the element may further include another componentinstead of excluding another component unless there is differentdisclosure.

It will be understood that when an element is referred to as being“between” two elements, it can be the only element between the twoelements, or one or more intervening elements may also be present. Likereference numerals refer to like elements throughout.

FIG. 1 illustrates an embodiment of a display device which includes apanel 102, a scan driver 110, a data driver 120, a sensing line 130, anda pixel unit 140. The pixel unit 140 includes pixels PXL connected todata lines D and scan lines S. Each pixel PXL emits light with apredetermined brightness based on data signals.

When the display device is an organic light emitting display device,each pixel PXL includes a plurality of transistors (including a drivingtransistor) and an organic light emitting diode (OLED). The pixels PXLare selected when scan signals are supplied to the scan lines S and emitlight based on the data signals from the data lines D. The drivingtransistors in the pixels PXL supply currents to OLEDs based on datasignals, and the OLEDs emit light components with predeterminedbrightness components based on the data signals.

When the display device is a liquid crystal display device, each pixelPXL includes a switching transistor and a liquid crystal capacitor. Thepixels PXL are selected when the scan signals are supplied to the scanlines S and receive the data signals from the data lines D. Then, thepixels PXL control transmittance of liquid crystal based on the datasignals, so that light components with predetermined brightnesscomponents are emitted.

The scan driver 110 supplies the scan signals to the scan lines S. Forexample, the scan driver 110 may sequentially supply the scan signals tothe scan lines S. The pixels PXL may be selected in units of horizontallines.

The data driver 120 supplies the data signals to the data lines D. Forexample, the data driver 120 may supply the data signals to the datalines D in synchronization with the scan signals. Then, the data signalsare supplied to the pixels PXL selected by the scan signals. The datadriver 120 is connected to pads to receive various voltages and/orsignals including data. The data driver 120 includes a plurality ofintegrated circuits mounted in the panel 102.

At least one sensing line 130 is formed as a wiring line for detectingcrack of the panel 102. The sensing line 130 may be formed, for example,at an edge of the panel 102 to allow for crack detection. Ends of thesensing line 130 are electrically connected to the data driver 120. Forexample, the sensing line 130 may be connected from one side of the datadriver 120 to another side of the data driver 120, via the edge of thepanel 102, so that the sensing line 130 has predetermined capacitanceand resistance. Therefore, when a crack occurs in panel 102, theresistance of sensing line 130 changes.

For example, when a crack occurs in the panel 102, the crack isgenerated in metal that forms the sensing line 130. When the crack isgenerated in the sensing line 130, resistance of the sensing line 130increases. Thus, according to one embodiment, a crack in the panel 102is detected based on a change in resistance of the sensing line 130. Inaddition, the sensing line 130 may be formed using at least one of themetals used in a process for forming the panel 102.

FIG. 2 illustrates an embodiment of the data driver 120 which includesat least two integrated circuits. In the example of FIG. 2, threeintegrated circuits 200, 201, and 202 are illustrated that supply datasignals to data lines D connected thereto.

Each of the integrated circuits 200, 201, and 202 includes apredetermined number of channels. For example, each of the integratedcircuits 200, 201, and 202 may have a uniform number of channels, e.g.,384 or 480. Since each of the integrated circuits 200, 201, and 202 hasa uniform number of channels, the number of integrated circuits 200,201, and 202 in data driver 120 increases in accordance with an increasein resolution of the panel 102.

When a crack occurs in the panel 102, the integrated circuits 200, 201,and 202 may be simultaneously reset. For example, when a crack occurs inthe panel 102, an image with desired brightness is not displayed by thepixel unit 140. In this case, an overcurrent (or overvoltage) may besupplied from the integrated circuits 200, 201, and 202 to the panel 102so that the image with the desired brightness is displayed by the pixelunit 140. Therefore, a fire may break out in the panel 102. In order toprevent fire from breaking out in the panel 102, according to theembodiment, the integrated circuits 200, 201, and 202 are simultaneouslyreset when a crack occurs in the panel 102.

In order to reduce or minimize dead space of the panel 102, variouselements including an element for supplying the data signals may beincluded in the integrated circuits 200, 201, and 202.

FIG. 3 illustrates an embodiment of an integrated circuit representativeof the integrated circuits in FIG. 2. The integrated circuit 200 in FIG.3 includes a voltage unit 210, interface unit 220, data processing unit230, channel unit 240, and a memory 250.

The voltage unit 210 generates voltages for driving the panel 102. Forexample, the voltage unit 210 may supply a gate high voltage VGH and agate low voltage VGL to the scan driver 110. In addition, the voltageunit 210 may generate a gamma reference voltage Vreg for generatinggamma voltages and an initializing voltage Vint for initializing thepixels PXL. Thus, the voltage unit 210 generates various voltages fordriving the panel 102.

The interface unit 220 receives various signals and data from anexternal system. When the panel 102 is in a portable device, theinterface unit 220 may include a mobile industry processor interface(MIPI). The MIPI is an interface with low power consumption, a hightransmission speed, and high expandability, and thus may be used for theportable device.

The data processing unit 230 rearranges the data supplied via theinterface unit 220 in accordance with the resolution of the panel 102,and stores the rearranged data in the memory 250. The data processingunit 230 processes the data stored in the memory 250 using, for example,a picture quality improving algorithm and a command (for example,brightness control) supplied via the interface unit 220.

The memory 250 stores the data and may be a random access memory (RAM)or another type of memory.

The channel unit 240 receives the data stored in the memory 250 andgenerates data signals based on control of the data processing unit 230.For example, the channel unit 240 may select one of a plurality of gammavoltages as a data signal based on a data bit. The data signalsgenerated by the channel unit 240 are supplied to data lines D.

FIG. 4 illustrates an embodiment of the interface unit 220 of FIG. 3which includes an MIPI 222 and a crack detecting unit 300. The MIPI 222is an interface which receives various signals and data from an externalsystem. The MIPI 222 has a standardized specification.

The crack detecting unit 300 transmits and receives informationcorresponding to the crack to and from adjacent integrated circuitsusing a transmission terminal Tx and a reception terminal Rx in thespecification of the MIPI 222.

The crack detecting unit 300 includes a voltage supplying/receiving unit302, a voltage detecting unit 304, a resetting unit 306, and atransmitting/receiving unit 308. The voltage supplying/receiving unit302 supplies or receives a predetermined voltage. For example, thevoltage supplying/receiving unit 302 supplies a predetermined voltage tothe sensing line 130 or receives the voltage supplied from the sensingline 130.

The voltage supplying/receiving unit 302 in the first integrated circuit200 of FIG. 2 may supply the predetermined voltage to the sensing line130. Then, the voltage supplying/receiving unit 302 in the thirdintegrated circuit 202 of FIG. 2 may receive the predetermined voltagefrom the sensing line 130. The voltage supplying/receiving unit 302 inthe second integrated circuit 202 not connected to the sensing line 130does not perform an operation at this time.

The voltage detecting unit 304 receives the voltage received by thevoltage supplying/receiving unit 302 and detects the level of thevoltage. When the voltage has a level lower than a predetermined level,the voltage detecting unit 304 supplies a detection signal to theresetting unit 306. For example, when a crack occurs in the panel 102,the resistance of the sensing line 130 increases. When the resistance ofthe sensing line 130 increases, the voltage received by the voltagedetecting unit 304 has a level lower than a predetermined level. In thiscase, the voltage detecting unit 304 supplies the detection signal tothe resetting unit 306.

The resetting unit 306 controls an entire operation of the crackdetecting unit 300. For example, when the detection signal is suppliedfrom the voltage detecting unit 304, the resetting unit 306 supplies anerror signal to an adjacent integrated circuit by using thetransmitting/receiving unit 308. The error signal may be a signalindicative of the crack of the panel 102.

When the error signal is received by the transmitting/receiving unit308, the resetting unit 306 may supply the error signal and/or a resetsignal to the adjacent integrated circuit using thetransmitting/receiving unit 308. The reset signal may be a signalcorresponding to an off state of the integrated circuit.

When the reset signal is received from the transmitting/receiving unit308, the resetting unit 306 sets the integrated circuit (one of 200,201, or 202) that includes the resetting unit 306 to an off state. Inone embodiment, the resetting unit 306 that receives the reset signalmay control the voltage unit 210, the data processing unit 230, thechannel unit 240, and the memory 250 to be in off states.

The transmitting/receiving unit 308 receives the error signal and/or thereset signal from the adjacent integrated circuit or transmits the errorsignal and/or the reset signal to the adjacent integrated circuit. Forthis purpose, the transmitting/receiving unit 308 may include thetransmission terminal Tx and the reception terminal Rx. The transmissionterminal Tx and the reception terminal Rx may be terminals included bythe specification of the MIPI 222. When the transmission terminal Tx andthe reception terminal Rx of the transmitting/receiving unit 308correspond to the specification of the MIPI 222, an additional terminalis not included in the integrated circuits 200, 201, and 202 in order totransmit/receive crack information of the panel 102. The omission ofthis additional terminal allows for a reduction in manufacturing costsand dead space.

The reset signal and the error signal may be previously allotted topredetermined data in accordance with the specification of the MIPI 222.For example, “000001” is set as the reset signal and “100001” may be setas the error signal. When the reset signal and the error signal aretransmitted/received by using the MIPI 222, a driving speed increases sothat the crack of the panel 102 may be detected within a short time.

In FIG. 4, the voltage supplying/receiving unit 302, the voltagedetecting unit 304, the resetting unit 306, and/or thetransmitting/receiving unit 308 are outside the MIPI 222. In oneembodiment, the voltage supplying/receiving unit 302, the voltagedetecting unit 304, the resetting unit 306, and/or thetransmitting/receiving unit 308 may be in the MIPI 222.

FIG. 5 illustrates an embodiment of a process for detecting a panelcrack and a process for resetting an integrated circuit. FIG. 6illustrates an embodiment of a method for inspecting a panel of adisplay device. The elements in the first integrated circuit 200 will bereferred to as “first elements,” the elements in the second integratedcircuit 201 will be referred to as “second elements,” and the elementsin the third integrated circuit 202 will be referred to as “thirdelements.”

Supply and/or Receive the Voltage: Operation S600

First, the first voltage supplying/receiving unit 302 in the firstintegrated circuit 200 supplies the predetermined voltage to the sensingline 130. The predetermined voltage from the first voltagesupplying/receiving unit 302 is supplied to the third voltagesupplying/receiving unit 302 in the third integrated circuit 202 via thesensing line 130.

Determine Whether a Normal Voltage is Received: Operation S602

The third voltage detecting unit 304 in the third integrated circuit 202determines whether the voltage received by the third voltagesupplying/receiving unit 302 is a normal voltage. For example, when thevoltage received by the third voltage supplying/receiving unit 302 has alevel no less than a predetermined level, the third voltage detectingunit 304 determines that the voltage is the normal voltage. When it isdetermined by the third voltage detecting unit 304 that the voltagereceived by the third voltage supplying/receiving unit 302 is the normalvoltage, operations S600 and S602 are repeated. Thus, when a crack isnot generated in the panel 102, operations S600 and S602 are repeated.

When the voltage received by the third voltage supplying/receiving unit302 has a level lower than the predetermined level, the third voltagedetecting unit 304 determines that the voltage is not the normalvoltage. In this case, the third voltage detecting unit 304 supplies thedetection signal to the third resetting unit 306 in the third integratedcircuit 202.

Transmit and/or Receive the Error Signal: Operation S604

The third resetting unit 306 that receives the detection signal suppliesthe error signal to the second transmitting/receiving unit 308 in thesecond integrated circuit 201 using the third transmitting/receivingunit 308. At this time, the second resetting unit 306 in the secondintegrated circuit 201 supplies the error signal to the firsttransmitting/receiving unit 308 in the first integrated circuit 200using the second transmitting/receiving unit 308.

Transmit and/or Receive the Reset Signal: Operation S606

When the error signal is received by the first transmitting/receivingunit 308, the first resetting unit 306 in the first integrated circuitgenerates the reset signal. The first resetting unit 306 that generatesthe reset signal supplies the reset signal to the secondtransmitting/receiving unit 308 using the first transmitting/receivingunit 308. The reset signal supplied to the second transmitting/receivingunit 308 is supplied to the second resetting unit 306. The secondresetting unit 306 that receives the reset signal supplies the resetsignal to the third transmitting/receiving unit 308 using the secondtransmitting/receiving unit 308.

Reset the Integrated Circuit: Operation S608

The first resetting unit 306 that generates the reset signal and thesecond resetting unit 306 and the third resetting unit 306 that receivethe reset signal turn off the voltage unit 210, the data processing unit230, the channel unit 240, and the memory 250 that are in each of theintegrated circuits 200, 201, and 202. Thus, the first through thirdresetting units 306 set the integrated circuits 200, 201, and 202 inwhich the first through third resetting units 306 are respectively to bein off states.

When the integrated circuits 200, 201, and 202 are in off states, powersources and the data signals are not supplied to the panel 102. Thus,when a crack occurs in the panel 102, the power sources and data signalsfor driving the panel 102 are not supplied. As a result, drivingstability may be secured.

In accordance with one or more of the aforementioned embodiments, a datadriver includes a plurality of integrated circuits. A first integratedcircuit supplies a predetermined voltage to another integrated circuitvia a sensing line. The other integrated circuit detects the level of avoltage from the sensing line and determines whether a crack occurs in apanel based on the detected level.

The methods, processes, and/or operations described herein may beperformed by code or instructions to be executed by a computer,processor, controller, or other signal processing device. The computer,processor, controller, or other signal processing device may be thosedescribed herein or one in addition to the elements described herein.Because the algorithms that form the basis of the methods (or operationsof the computer, processor, controller, or other signal processingdevice) are described in detail, the code or instructions forimplementing the operations of the method embodiments may transform thecomputer, processor, controller, or other signal processing device intoa special-purpose processor for performing the methods described herein.

The drivers, processors, units, interfaces areas, and other signalgenerating and processing features of the disclosed embodiments may beimplemented in logic which, for example, may include hardware, software,or both. When implemented at least partially in hardware, the drivers,processors, units, interfaces areas, and other signal generating andprocessing features may be, for example, any one of a variety ofintegrated circuits including but not limited to an application-specificintegrated circuit, a field-programmable gate array, a combination oflogic gates, a system-on-chip, a microprocessor, or another type ofprocessing or control circuit.

When implemented in at least partially in software, the drivers,processors, units, interfaces areas, and other signal generating andprocessing features may include, for example, a memory or other storagedevice for storing code or instructions to be executed, for example, bya computer, processor, microprocessor, controller, or other signalprocessing device. The computer, processor, microprocessor, controller,or other signal processing device may be those described herein or onein addition to the elements described herein. Because the algorithmsthat form the basis of the methods (or operations of the computer,processor, microprocessor, controller, or other signal processingdevice) are described in detail, the code or instructions forimplementing the operations of the method embodiments may transform thecomputer, processor, controller, or other signal processing device intoa special-purpose processor for performing the methods described herein.

In accordance with one or more of the aforementioned embodiments, when adetermination is made that a crack has occurred in the panel, an errorsignal from the other integrated circuit is sequentially supplied to thefirst integrated circuit and/or another integrated circuit. Then, areset signal corresponding to the error signal is sequentially suppliedto the first integrated circuit and one or more other integratedcircuits. The integrated circuits that receive the reset signal are setto off states to secure driving stability.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwiseindicated. Accordingly, various changes in form and details may be madewithout departing from the spirit and scope of the embodiments set forthin the claims.

What is claimed is:
 1. A display device, comprising: a sensing line in apanel; and a data driver including a plurality of integrated circuits,each of the integrated circuits including an interface which includes: amobile industry processor interface (MIPI) connected to an externalsystem; and a crack detector to detect a crack of the panel based on thesensing line and to transmit and receive information corresponding tothe crack to and from adjacent ones of the integrated circuits using atransmission terminal and a reception terminal in the MIPI.
 2. Thedisplay device as claimed in claim 1, wherein the sensing line includesa first side connected to a first integrated circuit among theintegrated circuits and a second side connected to a second integratedcircuit among the integrated circuits.
 3. The display device as claimedin claim 2, wherein the crack detector includes: a voltagesupplier/receiver to supply or receive a voltage to or from the sensingline; a voltage detector to determine whether the voltage from thevoltage supplier/receiver is a normal voltage; and reset logic connectedto the voltage detector to transmit and receive at least one of an errorsignal or a reset signal using the transmission terminal and thereception terminal.
 4. The display device as claimed in claim 3, whereinthe error signal is indicative of the crack of the panel.
 5. The displaydevice as claimed in claim 3, wherein the reset signal corresponds to anoff state of the first and second integrated circuits.
 6. The displaydevice as claimed in claim 3, wherein the error signal is to besequentially supplied to the second integrated circuit through the firstintegrated circuit.
 7. The display device as claimed in claim 3, whereinthe reset signal is to be sequentially supplied to the first integratedcircuit through the second integrated circuit.
 8. The display device asclaimed in claim 7, wherein the reset signal is to set the first andsecond integrated circuits in off states.
 9. The display device asclaimed in claim 3, wherein: when a level of the voltage is lower than apredetermined level, the voltage detector is to determine that thevoltage is an abnormal voltage and is to supply a detection signal tothe reset logic.
 10. The display device as claimed in claim 9, whereinthe reset logic is to supply the error signal to an adjacent one of theintegrated circuits.
 11. The display device as claimed in claim 1,wherein each of the integrated circuits includes: a voltage source tooutput a driving power source; a data processor to rearrange data itemssupplied via the interface and to store the rearranged data items in amemory; and a channel area to generate data signals based on the dataitems stored in the memory.
 12. The display device as claimed in claim11, wherein: when the crack occurs in the panel, the crack detector isto set the source, the data processor, the memory, and the channel areto be in off states.
 13. The display device as claimed in claim 1,wherein the sensing line is at an edge of the panel.
 14. A method forinspecting a display device including a mobile industry processorinterface (MIPI), the method comprising: supplying a predeterminedvoltage from a first integrated circuit in a data driver to a secondintegrated circuit in the data driver via a sensing line in a panel;determining, by the second integrated circuit, a level of thepredetermined voltage; and turning off integrated circuits in the datadriver when the voltage level is lower than a predetermined voltagelevel, wherein the first and second integrated circuits transmit andreceive information corresponding to crack of the panel using atransmission terminal and a reception terminal in the MIPI.
 15. Themethod as claimed in claim 14, wherein: when the voltage level is lowerthan the predetermined voltage level, the method includes generating, bythe second integrated circuit, an error signal.
 16. The method asclaimed in claim 15, wherein the error signal is sequentially suppliedto the second integrated circuit through the first integrated circuit.17. The method as claimed in claim 15, further comprising: generating areset signal, by the first integrated circuit, corresponding to theerror signal.
 18. The method as claimed in claim 17, further comprising:sequentially supplying the reset signal to the first and secondintegrated circuits.
 19. The method as claimed in claim 18, whereinreset signal turns off the first and second integrated circuits.